CVE-2026-114651

Cross-document data leak via malformed BSON array parsing in reused thread buffer

Published Oct 22, 2026 CVSS 4.0 · 6.3 Medium EPSS < 1% KEV · Not listed
Description
A memory-handling weakness in the BSON deserialization component of the MongoDB C# Driver may cause data left over from previously processed content to be returned when specially crafted serialized input is parsed. An unauthenticated party able to supply serialized data to an application that maps certain primitive collection types can cause residual bytes from unrelated data processed earlier on the same execution thread to be surfaced as legitimate values. This can result in disclosure of a limited amount of information belonging to other requests or principals of the consuming application. No authentication or special privileges within the application are required.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Mongodb
Mongodb c# Driver
Vendors & Products Mongodb
Mongodb c# Driver
Type Values Removed Values Added
Description A memory-handling weakness in the BSON deserialization component of the MongoDB C# Driver may cause data left over from previously processed content to be returned when specially crafted serialized input is parsed. An unauthenticated party able to supply serialized data to an application that maps certain primitive collection types can cause residual bytes from unrelated data processed earlier on the same execution thread to be surfaced as legitimate values. This can result in disclosure of a limited amount of information belonging to other requests or principals of the consuming application. No authentication or special privileges within the application are required.
Title Cross-document data leak via malformed BSON array parsing in reused thread buffer
Weaknesses CWE-908
References
Metrics cvssV3_1

{'score': 4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N'}

cvssV4_0

{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
mongodb
Published
Updated
Oct 30, 2026, 7:25 PM
Reserved
Oct 21, 2026, 9:57 PM
Status
Awaiting Analysis
Published
Oct 22, 2026, 7:17 PM
Modified
Oct 30, 2026, 8:17 PM